Electric switch



July 31, 1928; v 1,679,334

H. A. DOUGLAS mcnuc SWITCH Filed aamz m 192 Patented July 31, 1928.

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nanny A. nofiGLAs, or imoNsoN, ivrrcrrman .ELECTRIC SWITCH;

Application filed January '27, 1926. I Serial No. :84,098;u'

Myi invention relates ,to electrie switches.

formed of insulation, and which arei'ela 6 tivelyrotatable or otherwiserelatively movable to bring the contacts thereon into and out ofcontacting relation.

In other switches as at present constructed, the insulating contactcarrying member 1s 10 engaged by the contact upon the other member inthe adjustment of the switch to circuit opening and circuit closingpositions. Due to the friction between this contact and the insulatingmember, particles of insulation are worn from this member and arecarried by the contact engaging it causing imperfeet and resistanceproducing engagement between the contacts when brought into contactingalignment.

The device of my invention serves to move one contact carrying memberfrom the other when the switch is being adjusted so that the insulatincontact carrier will not then be engaged by the contact upon the othercontact carrier. One of the contact carriers has a portion engaging theother which causes this result when the contacts are out of contactingalignment, and permits the moved carrier to approach the other when thecontacts are in contacting alignment to permit engagement between thecontacts.

The invention will be more fully explained in connection with theaccompanying drawing in which Fig. 1 is a sectional view on line 1-1 ofFig. 2, on a smaller scale; Fig. 2 is a sectional view on line 22 ofFig. 1; Fig. 3 is a rear face View of a portion of one of the contactcarriers, showing a contact thereon; and Fig. 4 is a sectional view online 44 of Fig. 3.

The structure illustrated employs a casing having a front end wall 1 anda side wall 2, the Wall 1 being essentially flat and the wall 2 beingcylindrical. The rear end of the switch casing is closed by a contactcarrier 3 which is separably assembled with the easing by means ofbayonet pins 4 upon the contact carrier receivable in bayonet slots 5provided in the casing wall 2. The contact carrier carries contacts 6engageable by con tacts 7 that are carried upon a metallic ring 8,andwhich are coupled by means of the spring-pressed lungers 9 with acontact actuator 10 in tiie form of a ring of insulation. This contactactuator is assembled with the wings 11 extending inwardly from the hubportion--12iof a handlen13. The handle hub ,is provided with: aflanges-14; received between the endwall l -of the casin and thefinishing cover;plate,15, whereby the handle isconfined toan axis ofrotation which is coincident with the casing axis.

The coiled springs 16 that press the plungers 9 against the bottoms ofthe cupshaped cavities 17 in the insulating ring 10 are housed in springbarrels 18 which are carried by and project forwardly from the metallicring or contact carrying member 8. These springs not only press theplungers 9 forwardly but also press the metallic contact carrying member8 toward theinsulating contact carrying member 3, decreasing the spacebetwen the contact carriers when the contacts engage. The contacts 6 andthe contacts 7 are arranged upon a circle that is concentric with theaxis of the handle so that as the handle is turned, the contacts7 arebrought into and out of contacting alignment with their complementalcontacts 6 whereby the circuits including the engageable contacts areeither closed or opened. The contacts 7 are provided with portions 19rearwardly projecting therefrom and which ride or rest upon theinsulating member 3 to separate the carriers 3 and 8 further when thecontacts? are out of contacting alignment with their complementalcontacts 6, to separate contacts 7 from carrier 3 against the force ofsprings 16 for the purpose stated. The contacts 6 are formed withcup-shaped recesses 20 at their front ends which freely receive theprojecting portions 19 when the contacts 7 arerin contacting alignmentwith the contacts 6, to reduce the space between the carriers and'permitthe springs 16 to force engagement of the contacts. In order to avoidundue wear, the projecting portions 19 are desirably in the form ofrotatable balls which are received and turned within seats formed in thecontacts 7 and which are held in place by means of seats 21 that are inthe form of dished plates havlng ears 22 passing through the member 8whereby the seats 21 are rigidly secured to the member 8. The balls 19will gather but little, if any, of particles of insulation from theinsulating member 3 and whatever insulating particles may be gathered bythe balls do not find lodgement upon the portions of the contacts 7 thatare engageable with the contacts 6. Each ball is free of the tacts intoand out of contacting alignment, one of said contacts having a recess inits contacting face and the other contact having a ball projectingtherefrom and rotatable upon the carrier for the first Contact, saidball being receivable within said recess, the contact having the ballalso having another portion engageable with the other contact andholding the ball out of engagement with said other contact when thecontacts are in engagement.

In witness whereof, I hereunto subscribe my name.

HARRY A. DOUGLAS.

